decelerate vs modify

decelerate and modify both are verbs.

Word	Noun	Adjective	Verb	Adverb
decelerate	No	No	Yes	No
modify	No	No	Yes	No

As verbs, modify is a hypernym of decelerate; that is, modify is a word with a broader meaning than decelerate:

Other hypernyms of decelerate include alter, change.

decelerate (verb)	modify (verb)
lose velocity; move more slowly	make less severe or harsh or extreme
reduce the speed of	add a modifier to a constituent
	cause to change; make different; cause a transformation